First up: Obama. What's changed on this front? Mostly, time: the bitter nomination battle (on a poodle with a paddle in the water on a turtle....) is over. Clinton supporters have mostly forgiven the opposition and both Hillary and Bill have aired their laundry with Obama and "gotten past that" and on board with being just another Obamabot fan. She's also been largely written off by the punditocracy. That in itself improves Hillary's chances tremendously.

Look: there is still no more energizing candidate out there for Obama than Hillary. By announcing a Hillary Clinton VP at the start of the convention, Obama can shape the narrative of unity going both into and out of the convention, and create a media frenzy the world has never before seen - the "unity ticket" would go on the stump immediately after the convention and such all the media air out of the Republican convention. Between the money and the media interest, McCain would become just a footnote to his own race. There would be no stopping the momentum.

Plus, Hillary has turned into, in her own right, perhaps the second best Democratic politician in this country right now. (Yes, the old Bill I used to love is now but a memory.) From a pure talent standpoint, Obama would be hard pressed to claim that there's anyone better.

There's just one problem. What does Obama do with the Clintons once he gets to the White House? Conservative Clinton-hating Obama fans like Andrew Sulliven would be apoplectic; Bill would be a liability; Michele has supposedly nixed the entire idea. There's a lot of feeling in camp Obama and around that the Clinton's are supposedly done, now, and not to be kept hanging around.

But Hillary is not done. And Obama wants his rivals close. Veep is as good a spot for her as anything.

The only issue, really is this: Obama is doing so well on his own, he may not need her. If he can do it without her, he probably will. So we'll have to wait and see; if the race starts to narrow in August, look for the big H to be pulled out on Day One in Denver. If Obama's six point margin turns to 8 or 10, then go to scenario two:

Scenario Two: Someone who isn't Hillary.

This list is harder to penetrate. Was the whole Clark fiasco Obama's way of auditioning him for VP? McCain wants Obama to "cut him lose," whatever that means - but what better way to get up McCain's rear than to put this guy on the ticket?

Maybe that's a bit too in-your-face, though. If Obama turns to his other short list, he's basically got Biden, Nunn, Richardson, and Edwards to pick from; or if he wants a general who isn't Clark, the basically unknown James Jones. (I'd say, with the amazingly lingering still-sore feelings of a significant minority of Hillarybots, all women who aren't Hillary are off the ticket.)

How do we chose amongst these five? How do we rank amongst these five? Really, it's hard to say - they all have assets in different ways. But if Obama is 10 or more points ahead of McCain in polls going into August, and a real rout looks possible, Obama doesn't need his selection to do any particular thing for him. He just needs someone who won't be controversial and who'll be the best asset for governing come January. In that case, my money would be on Biden. I've always liked Biden - he could have been a Bill Clinton without the baggage, if he only hadn't lifted a bit of his speech from some limey years ago. That's largely a non-issue for a Veep that won't be competing with Obama for head of the oratory spotlight. Biden always seems smart, experienced, educated on the details of the issues without seeming overly wonky. When the young Obama wants to turn to someone for advice, I could hardly think of anyone better to do the job.

So it comes down to this: Obama ahead by less than 6 - look for a big Hillary anouncement day one of the convention. Obama pulls his lead out to 10 or so - Biden's put on the ticket during the Olympics. Polls stay somewhere in between...it's anyone's guess.